Automated Under Frequency Load Shedding (AUFLS) Project

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What is Automated Under-Frequency Load Shedding Project?

AUFLS is the acronym for Automatic Under-Frequency Load Shedding and describes the set of relays in New Zealand which automatically trip blocks of load, following a severe under-frequency event, to restore the system frequency.

Transpower as System Operator relies on the AUFLS scheme to prevent system collapse following under-frequency events which have the potential to cause a system black-out.

Under previous Code arrangements, North Island AUFLS providers, and Transpower as grid owner in the South Island, must arm two blocks of load for AUFLS provision. The total load armed in each block must be at least 16% of the provider’s total network demand. Each provider must provide information that either complies with the technical codes or is reasonably requested by the System Operator, to assist in the System Operator planning to comply and complying with its principal performance obligations. North Island AUFLS providers have been required to provide this data annually, via submitting their Distributor Asset Capability Statement spreadsheets. In addition to the System Operator providing regular reporting, following an Extended Contingent Event, the System Operator will complete analysis of the performance of the AUFLS scheme and request that North Island AUFLS providers provide specific AUFLS data.

Background information – Development of the North Island AUFLS four block scheme proposal

Between 2010 and 2013, the Electricity Authority (Authority) reviewed the AUFLS arrangements and identified that the scheme could be amended to improve overall performance. The Authority has been working with the System Operator to develop a proposal for these amendments – moving from a two-block to a four-block AUFLS scheme.

Details of the decision to implement a four-block AUFLS scheme can be found on the Authority’s website.

Project Timeline

The AUFLS Project is delivered in 4 phases.

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The first phase of the project was completed early 2022. Phase 4 commenced in January 2024. The project is expected to be completed by end June 2025.

Ongoing Industry Involvement / Contact Us

The System Operator will actively engage with the North Island AUFLS providers over the duration of the project. This will be through industry workshops, one-on-one direct engagement and through provision of supporting material.   

You can send your queries regarding the AUFLS Project to [email protected].  

Transition Quarterly Industry Presentations

September 2024 Presentation

Topics	Supporting Documents
Celebrate reaching halfway point AUFLS transition dashboard Lessons learnt Testing requirements HVDC Flow Studied: Before and Actual Question and Feedback	Presentation

June 2024 Presentation

Topics	Supporting Documents
High level recap on the AUFLS transition process AUFLS transition dashboard Lessons learnt BAU requirements linked to the transition High level overview of studies and results Question and Feedback	Presentation

March 2024 Presentation

Topics	Supporting Documents
High level recap on the AUFLS transition process EA Report AUFLS transition Dashboard Lesson Learnt BAU requirements linked to the transition BAU: Annual load data submission Question and Feedback	Presentation

Industry Workshops

2023

Workshop 8-9 November 2023

Transition Plan Industry Workshop

The following material is a combination of what was presented at the Transition Plan Workshop and answers to questions that were raised at the workshops:

Topics	Supporting Documents
Electricity Authority Update System Operator Updates Transition Plan Summary Recap Transition (Change) Process detailed What’s next	Presentation Q and A

Workshop 12-13 July 2023

Transition Plan Industry Workshop

The following material is a combination of what was presented at the Transition Plan Workshop and answers to questions that were raised at the workshops:

Topics	Supporting Documents
Transition timeframes Submissions and main observations Study approach and assumptions Study results and findings Transition plan What’s next?	Presentation Q and A

2022

Workshop 16-17 Nov 2022

Planning for Transition Workshop

The following material is a combination of what was presented at the AUFLS Transition Workshop and answers to questions that were raised at the workshops:

Topics	Supporting Documents
Electricity Authority update Transition timeframes Transition planning Assessment approach What we need from you	Presentation Q and A AUFLS Provider individual transition plan template

2021

Workshop 15-16 Nov 2021

AUFLS Data Portal Roll-out Training Workshop

The following material is a combination of what was presented at the AUFLS Training Workshop and answers to questions that were raised at the workshops:

Topics	Supporting Documents
AUFLS Customer Portal Roll-Out Update Authority Extended Reserves (AUFLS) Code Consultation Update   System Operator ATR Document Consultation Update  AUFLS Customer Portal – Data Requirements Refresh AUFLS Customer Portal – Load Profile Data Upload Run-Through Ongoing Engagement	Presentation Q and A

Workshop 20-21 Sep 2021

AUFLS Data Portal Roll-out Training Workshop

The following material is a combination of what was presented at the AUFLS Training Workshop on 20-21 Sep and answers to questions that were raised at the workshops:

Topics	Supporting Documents
Authority Extended Reserves (AUFLS) Code Consultation Update System Operator ATR Document Consultation Update AUFLS Customer Portal Roll-Out Timeframes AUFLS Customer Portal – Data Requirements Refresh AUFLS Customer Portal – Feeder Config Data Run-Through Ongoing Engagement	Presentation Q and A

Workshop 12 & 15 Jul 2021

UFLS Data Portal Roll-out Training Workshop

The following material is a combination of what was presented at the AUFLS Training Workshop and answers to questions that were raised at the workshops:

Topics	Supporting Documents
Workshop Objectives AUFLS Project Background and Overview AUFLS Data Portal and Benefits AUFLS Data Portal Roll-Out and what is involved AUFLS Data Portal Demonstration and Walkthrough Ongoing Engagement	Presentation Q and A

Related information / Documentation

For more background information on the AUFLS scheme, the AUFLS Operations Customer Portal, learning animations, FAQs, and user guides, see the AUFLS web page.